版权声明:是自己手打的没错 https://blog.csdn.net/Mr_Treeeee/article/details/81665330
http://acm.fzu.edu.cn/problem.php?pid=2082
边权模板。
修改一个,查询区间。
#include <stdio.h>
#include <string.h>
#include <iostream>
#include <algorithm>
#include <vector>
#include <queue>
#include <set>
#include <map>
#include <string>
#include <math.h>
#include <stdlib.h>
using namespace std;
#define LL long long
const int MAXN = 50000+22;
struct Edge
{
int to,next;
}edge[MAXN*2];
int head[MAXN],tot;
int top[MAXN];//top[v]表示v所在的重链的顶端节点
int fa[MAXN]; //父亲节点
int deep[MAXN];//深度
int num[MAXN];//num[v]表示以v为根的子树的节点数
int p[MAXN];//p[v]表示v与其父亲节点的连边在线段树中的位置
int fp[MAXN];//和p数组相反
int son[MAXN];//重儿子
int pos;
void init()
{
tot = 0;
memset(head,-1,sizeof(head));
pos = 0;
memset(son,-1,sizeof(son));
}
void addedge(int u,int v)
{
edge[tot].to = v;edge[tot].next = head[u];head[u] = tot++;
}
void dfs1(int u,int pre,int d) //第一遍dfs求出fa,deep,num,son
{
deep[u] = d;
fa[u] = pre;
num[u] = 1;
for(int i = head[u];i != -1; i = edge[i].next)
{
int v = edge[i].to;
if(v != pre)
{
dfs1(v,u,d+1);
num[u] += num[v];
if(son[u] == -1 || num[v] > num[son[u]])
son[u] = v;
}
}
}
void getpos(int u,int sp) //第二遍dfs求出top和p
{
top[u] = sp;
if(son[u] != -1)
{
p[u] = pos++;
fp[p[u]] = u;
getpos(son[u],sp);
}
else
{
p[u] = pos++;
fp[p[u]] = u;
return;
}
for(int i = head[u] ; i != -1; i = edge[i].next)
{
int v = edge[i].to;
if(v != son[u] && v != fa[u])
getpos(v,v);
}
}
//线段树
struct Node
{
int l,r;
LL sum;
}segTree[MAXN*3];
void build(int i,int l,int r)
{
segTree[i].l = l;
segTree[i].r = r;
segTree[i].sum = 0;
if(l == r)return;
int mid = (l+r)/2;
build(i<<1,l,mid);
build((i<<1)|1,mid+1,r);
}
void push_up(int i)
{
segTree[i].sum = segTree[i<<1].sum+segTree[(i<<1)|1].sum;
}
void update(int i,int k,int val) // 更新线段树的第k个值为val
{
if(segTree[i].l == k && segTree[i].r == k)
{
segTree[i].sum =1LL*val;
return;
}
int mid = (segTree[i].l + segTree[i].r)/2;
if(k <= mid)update(i<<1,k,val);
else update((i<<1)|1,k,val);
push_up(i);
}
LL query(int i,int l,int r) //查询线段树中[l,r] 的最大值
{
if(segTree[i].l == l && segTree[i].r == r)
return segTree[i].sum;
int mid = (segTree[i].l + segTree[i].r)/2;
if(r <= mid)return query(i<<1,l,r);
else if(l > mid)return query((i<<1)|1,l,r);
else return query(i<<1,l,mid)+query((i<<1)|1,mid+1,r);
}
LL find(int u,int v)//
{
int f1 = top[u], f2 = top[v];
LL tmp = 0;
while(f1 != f2)
{
if(deep[f1] < deep[f2])
{
swap(f1,f2);
swap(u,v);
}
tmp += query(1,p[f1],p[u]);
u = fa[f1]; f1 = top[u];
}
if(u == v)return tmp;
if(deep[u] > deep[v]) swap(u,v);
return tmp+query(1,p[son[u]],p[v]);
}
int e[MAXN][3];
int main()
{
int n,m;
while(~scanf("%d%d",&n,&m)){
init();
for(int i = 0;i < n-1;i++)
{
scanf("%d%d%d",&e[i][0],&e[i][1],&e[i][2]);
addedge(e[i][0],e[i][1]);
addedge(e[i][1],e[i][0]);
}
dfs1(1,0,0);
getpos(1,1);
build(1,0,pos-1);
for(int i = 0;i < n-1; i++)
{
if(deep[e[i][0]] > deep[e[i][1]])
swap(e[i][0],e[i][1]);
update(1,p[e[i][1]],e[i][2]);
}
while(m--)
{
int k,a,b;
scanf("%d%d%d",&k,&a,&b);
if(k==0)
update(1,p[e[a-1][1]],b);
else{
printf("%lld\n",find(a,b));
}
}
}
return 0;
}